Centerless grinding machine



llgr. 3l', 1937. A-sCR|\ /ENER 2,091,655

CENTERLESS GRINDING 'MACHINE Filed Dc.' 3o, l1935 A 35 Figure 3 grindingposition but with the backing 'wheel or ranma Aug. 31, 1937 ,UNITEDs'rn'ras 2,091,855 cnwrnnnass aannamesmcnmn Arthur Scrlvener,Birmingham'England Application This invention is for improvements inconnection with centerless grinding machines, of the kind in which thework is supported on a rest and is mechanically rotated in pressurecontact with a grinding wheel, and in which the work is presented to andwithdrawn from the grinding wheel by means of or under control of abacking wheel or cam which also constitutes the work-rotating device.

The object is to provide a centerless grinding machine o! this kindwhich shall be highly eilicient and reliable in operation for therepetition grinding of screw-threaded bolts,- studs, and other helicallysurfaced work. and which in particular l shall ensure that the work' iscorrectly aligned in relationto the grinding wheel before being .broughtinto contact therewith.

According to the present invention, in a centerless grinding machineofethe kind referred to, m the screw-threads on the work are correctlyaligned in relation to annular serrations on the grinding wheel by meansof a radial control iinger which is adapted ior,universal adjustment. Inorder that the invention may be clearly g5 understood and readilycarried into practice, reference may be had to the appended explanatorydrawing illustrating a convenient method o! carrying the invention intoeiIect, and in whichl:-

Figure 1 is a, diagrammatic side elevation of a part of the machineshowing the work fed into position on the rest in readiness forpresentation to the grinding wheel.

Figure 2 is a similar view showing the advanced into grinding Position.

is a re'ar elevation with the work in work cam removed.

In the arrangement illustrated, the work a is supportedv during thegrinding operation upon a 40 rest b upstanding in close proximity to thegrinding wheel c, which is formed with annular serra. tions c1 adaptedfor accurate grinding of the proiile of the screw-threads a1 on thework, the rest h being inclined away lfrom the grinding 4l wh'eel c atthe top as upright reariace recessed in arcuate. form as shown at b.

The work a is movable laterally over this supporting rest b, towards andaway from the grinding wheel c, under control of a backing wheel or camd which is mounted behind the grinding wheel, preferably in. such amanner as to be adapted tor advancing and retracting movements inrelation to the Great Britain January 1o, 1 1 Claim (Cl. .5l-103) eachrevolution of axis of the grinding shown at b1, and having itsl grindingwheel, in conjunctionii desired with a spring-loaded guide e operating fDecember 3c. 1935, semi gro. sass?,

in opposed' relation to the cam. This backing wheel or cam d is shapedto feed the work a Iorwards over the supporting rest b from a loadingposition clear of the wheel c as shown in Figure l, into a grindingposition in contact with the wheel c as shown in Figures' 2 and 3, thento rotate the -work a through one revolution or more than one revolutionwith suillcient pressure to grind the surface being treated, and then topermit of the work a falling away from the grinding wheel c, this rcycleoi' operations taking place twice during the continuously rotating.double-acting cam d illustrated. The backing wheel or cam however maybe oi a continuously rotating single-acting form, or may be arranged foroscillation in opposite directions alternately. The backing wheel .orcam d for presenting kand rotating the work a operates in associationwith an adjustable control finger f abutting radially on the top of thework for ensuring correct alignment of the screw-threads a1 on the worka with the annular serrations c1 in the grinding'wheel c before the worka touches'the grinding wheel. This linger j, having a serrated tip I1which conforms substantially to the profile of the screwthreads lnl onthe workand which is preferably spring-loaded as shown at P, isuniversally adinstable in relation to .the work a, that is to say, ithas a ne `inicrrneter adjustment by screw h and slide block iindirections parallel to the wheel c, and is also adjusta and grindingwheel c, the horizontal ment being eiIected-by hand-wheel y' and slidebloei; k, and the verticaladjustment by sliding the finger within theslide block i under control oi' a locking stud l, the control finger fbeing also i rniationally adjustable under control of said stud I forlocation of its serrations at the correct helix angle of thescrew-thread being gr/ound.

It will be seen that on the adjustable control linger f being initiallyset, the backing wheel or -cani d provides for a continuous successionalfeed I work to the grinding wheel c. The workrotating backing wheel orcam d together with the work-supporting rest. b may be withdrawn fromthe grinding position whilst the work a is placed' on the rest b' incontact with the backing wheel or cam d. The whole unit carrying with itthe work-piece a' may v`then be advanced into the working positionwhilst the work is treated, and on completion be withdrawn again forunloading purpocs. This cycle o! operations may 10 adapted to rotate thework upon said rest in pressure contact with the grinding wheel and alsoto control the presentation and withdrawal oi.' the work to and from thegrinding wheel, and a serrated control tlnger abutting radially on thework upon saidV rest, said nnger being adapted 5 for universaladjustment so as to ensure that the; screw-threads on the work arecorrectly aligned in relation to the annular serrations on the grindingwheel.

ARTHUR SCRIVENER. I0

